The barycenter of ordinary flat purlins is located above the main beam, when the main beam rotates at a certain angle, the barycenter of the purlins and solar panels will deviate from the pivot of the main beam, resulting in an eccentric torque. Therefore, when the slewing drive rotates, it is not only necessary to overcome the friction of the supporting bearing itself, but also to overcome the torsion force caused by the eccentric torque, which inevitably increases the power consumption of the motor.